Stem cells have the potential to cure numerous disease and disorders. However, the sources of stem cells are limited. A representative example of the problem with obtaining stem cells is illustrated by human umbilical cord blood (UCB) hematopoietic stem/progenitor cells (HSPCs). HSPCs are multipotent cells that have the capacity to self-renew and differentiate into all mature blood cell types. However, the low number of HSPCs obtainable from umbilical cords due to the small volume of blood collected limits direct UCB HSPC transplantation treatments to pediatric patients. Therefore, several approaches have been explored to expand HSPCs in ex vivo expansion systems, so that UCB could serve as a readily viable source of transplantable HSPCs for adult patients suffering from a variety of disorders.
In conventional ex vivo expansion culture, HSPCs are generally regarded as suspension cells and numerous protocols implement HSPC suspension cultures in flasks or bags in the presence of various combinations of early acting cytokines. These protocols do not produce enough stem cells to be of clinical significance. Similar problems exist with the expansion of other types of stem cells.
Accordingly, the need exists for improved methods and compositions for the expansion and differentiation of stem cells.